1*0a6a1f1dSLionel Sambuc /* $NetBSD: flt_rounds.c,v 1.1 2014/08/10 05:47:36 matt Exp $ */
2*0a6a1f1dSLionel Sambuc
3*0a6a1f1dSLionel Sambuc /*-
4*0a6a1f1dSLionel Sambuc * Copyright (c) 2014 The NetBSD Foundation, Inc.
5*0a6a1f1dSLionel Sambuc * All rights reserved.
6*0a6a1f1dSLionel Sambuc *
7*0a6a1f1dSLionel Sambuc * This code is derived from software contributed to The NetBSD Foundation
8*0a6a1f1dSLionel Sambuc * by Matt Thomas of 3am Software Foundry.
9*0a6a1f1dSLionel Sambuc *
10*0a6a1f1dSLionel Sambuc * Redistribution and use in source and binary forms, with or without
11*0a6a1f1dSLionel Sambuc * modification, are permitted provided that the following conditions
12*0a6a1f1dSLionel Sambuc * are met:
13*0a6a1f1dSLionel Sambuc * 1. Redistributions of source code must retain the above copyright
14*0a6a1f1dSLionel Sambuc * notice, this list of conditions and the following disclaimer.
15*0a6a1f1dSLionel Sambuc * 2. Redistributions in binary form must reproduce the above copyright
16*0a6a1f1dSLionel Sambuc * notice, this list of conditions and the following disclaimer in the
17*0a6a1f1dSLionel Sambuc * documentation and/or other materials provided with the distribution.
18*0a6a1f1dSLionel Sambuc *
19*0a6a1f1dSLionel Sambuc * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20*0a6a1f1dSLionel Sambuc * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21*0a6a1f1dSLionel Sambuc * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22*0a6a1f1dSLionel Sambuc * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23*0a6a1f1dSLionel Sambuc * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24*0a6a1f1dSLionel Sambuc * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25*0a6a1f1dSLionel Sambuc * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26*0a6a1f1dSLionel Sambuc * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27*0a6a1f1dSLionel Sambuc * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28*0a6a1f1dSLionel Sambuc * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29*0a6a1f1dSLionel Sambuc * POSSIBILITY OF SUCH DAMAGE.
30*0a6a1f1dSLionel Sambuc */
31*0a6a1f1dSLionel Sambuc
32*0a6a1f1dSLionel Sambuc #include <sys/cdefs.h>
33*0a6a1f1dSLionel Sambuc #if defined(LIBC_SCCS) && !defined(lint)
34*0a6a1f1dSLionel Sambuc __RCSID("$NetBSD: flt_rounds.c,v 1.1 2014/08/10 05:47:36 matt Exp $");
35*0a6a1f1dSLionel Sambuc #endif /* LIBC_SCCS and not lint */
36*0a6a1f1dSLionel Sambuc
37*0a6a1f1dSLionel Sambuc #include <sys/param.h>
38*0a6a1f1dSLionel Sambuc #include <sys/types.h>
39*0a6a1f1dSLionel Sambuc #include <ieeefp.h>
40*0a6a1f1dSLionel Sambuc
41*0a6a1f1dSLionel Sambuc #include <aarch64/armreg.h>
42*0a6a1f1dSLionel Sambuc
43*0a6a1f1dSLionel Sambuc
44*0a6a1f1dSLionel Sambuc /*
45*0a6a1f1dSLionel Sambuc * Return the current FP rounding mode
46*0a6a1f1dSLionel Sambuc *
47*0a6a1f1dSLionel Sambuc * Returns:
48*0a6a1f1dSLionel Sambuc * 0 - round to zero
49*0a6a1f1dSLionel Sambuc * 1 - round to nearest
50*0a6a1f1dSLionel Sambuc * 2 - round to postive infinity
51*0a6a1f1dSLionel Sambuc * 3 - round to negative infinity
52*0a6a1f1dSLionel Sambuc *
53*0a6a1f1dSLionel Sambuc * However, the rounding modes stored in the FPCR are:
54*0a6a1f1dSLionel Sambuc * 0 - round to nearest
55*0a6a1f1dSLionel Sambuc * 1 - round to postive infinity
56*0a6a1f1dSLionel Sambuc * 2 - round to negative infinity
57*0a6a1f1dSLionel Sambuc * 3 - round to zero
58*0a6a1f1dSLionel Sambuc *
59*0a6a1f1dSLionel Sambuc * To convert, just add 1 and then mask with 3.
60*0a6a1f1dSLionel Sambuc */
61*0a6a1f1dSLionel Sambuc
62*0a6a1f1dSLionel Sambuc int __flt_rounds(void);
63*0a6a1f1dSLionel Sambuc
64*0a6a1f1dSLionel Sambuc int
__flt_rounds(void)65*0a6a1f1dSLionel Sambuc __flt_rounds(void)
66*0a6a1f1dSLionel Sambuc {
67*0a6a1f1dSLionel Sambuc return (__SHIFTOUT(reg_fpcr_read(), FPCR_RMODE) + 1) & 3;
68*0a6a1f1dSLionel Sambuc }
69